<template>
  <div class="scrollbar">
    <div
      ref="wrap"
      :class="[
        wrapClass,
        'scrollbar__wrap',
        native ? '' : 'scrollbar__wrap--hidden-default',
      ]"
      :style="wrapStyle"
      @scroll="handleScroll"
    >
      <component
        :is="tag"
        ref="resize"
        :class="['scrollbar__view', viewClass]"
        :style="viewStyle"
      >
        <slot></slot>
      </component>
    </div>
    <template v-if="!native">
      <bar :move="moveX" :size="sizeWidth" />
      <bar vertical :move="moveY" :size="sizeHeight" />
    </template>
  </div>
</template>
<script lang="ts" setup>
import {
  ref,
  onMounted,
  onBeforeUnmount,
  nextTick,
  provide,
  unref,
  watch,
  type PropType,
} from "vue";
import type { StyleValue } from "@/utils/types";
import { addResizeListener, removeResizeListener } from "@/utils/event";
import componentSetting from "@/settings/componentSetting";
import Bar from "./bar";

defineOptions({ name: "Scrollbar" });

const props = defineProps({
  native: {
    type: Boolean,
    default: componentSetting.scrollbar?.native ?? false,
  },
  wrapStyle: {
    type: [String, Array, Object] as PropType<StyleValue>,
    default: "",
  },
  wrapClass: {
    type: [String, Array],
    default: "",
  },
  viewClass: {
    type: [String, Array],
    default: "",
  },
  viewStyle: {
    type: [String, Array],
    default: "",
  },
  noresize: Boolean, // 如果 container 尺寸不会发生变化，最好设置它可以优化性能
  tag: {
    type: String,
    default: "div",
  },
  scrollHeight: {
    // 用于监控内部scrollHeight的变化
    type: Number,
    default: 0,
  },
});

const sizeWidth = ref("0");
const sizeHeight = ref("0");
const moveX = ref(0);
const moveY = ref(0);
const wrap = ref();
const resize = ref();

provide("scroll-bar-wrap", wrap);

const handleScroll = () => {
  if (!props.native) {
    moveY.value = (unref(wrap).scrollTop * 100) / unref(wrap).clientHeight;
    moveX.value = (unref(wrap).scrollLeft * 100) / unref(wrap).clientWidth;
  }
};

const update = () => {
  if (!unref(wrap)) return;

  const heightPercentage =
    (unref(wrap).clientHeight * 100) / unref(wrap).scrollHeight;
  const widthPercentage =
    (unref(wrap).clientWidth * 100) / unref(wrap).scrollWidth;

  sizeHeight.value = heightPercentage < 100 ? heightPercentage + "%" : "";
  sizeWidth.value = widthPercentage < 100 ? widthPercentage + "%" : "";
};

watch(
  () => props.scrollHeight,
  () => {
    if (props.native) return;
    update();
  },
);

defineExpose({
  wrap,
});

onMounted(() => {
  if (props.native) return;
  nextTick(update);
  if (!props.noresize) {
    addResizeListener(unref(resize), update);
    addResizeListener(unref(wrap), update);
    addEventListener("resize", update);
  }
});

onBeforeUnmount(() => {
  if (props.native) return;
  if (!props.noresize) {
    removeResizeListener(unref(resize), update);
    removeResizeListener(unref(wrap), update);
    removeEventListener("resize", update);
  }
});
</script>
<style lang="less">
.scrollbar {
  position: relative;
  height: 100%;
  overflow: hidden;

  &__wrap {
    height: 100%;
    overflow: auto;

    &--hidden-default {
      scrollbar-width: none;

      &::-webkit-scrollbar {
        display: none;
        width: 0;
        height: 0;
        opacity: 0;
      }
    }
  }

  &__thumb {
    display: block;
    position: relative;
    width: 0;
    height: 0;
    transition: 0.3s background-color;
    border-radius: inherit;
    background-color: rgb(144 147 153 / 30%);
    cursor: pointer;

    &:hover {
      background-color: rgb(144 147 153 / 50%);
    }
  }

  &__bar {
    position: absolute;
    z-index: 1;
    right: 2px;
    bottom: 2px;
    transition: opacity 80ms ease;
    border-radius: 4px;
    opacity: 0;

    &.is-vertical {
      top: 2px;
      width: 6px;

      & > div {
        width: 100%;
      }
    }

    &.is-horizontal {
      left: 2px;
      height: 6px;

      & > div {
        height: 100%;
      }
    }
  }
}

.scrollbar:active > .scrollbar__bar,
.scrollbar:focus > .scrollbar__bar,
.scrollbar:hover > .scrollbar__bar {
  transition: opacity 340ms ease-out;
  opacity: 1;
}
</style>
